Banana Slug Biology

Janet Leonard and John Pearse gave a presentation on banana slug biology.

• Habitat: Found in conifer forests and open woodlands. Along the coast from southeast Alaska to as far south as Mount Palomar.

• Diet: Banana slugs are omnivores and feed on soil, plants, mushrooms, feces.
• Variation in color: Species of banana slugs vary in their coloration: uniform or spotted. Dark or light. Coloration is used as camouflage.
• Predators: garter snakes, salamanders and newts, birds and small mammals, carnivores snails and slugs.

Ariolimax californicus, brachyphallus and dolichophallus are all found on the San Francisco peninsula.

The cladogram based on mitochondrial 16S sequences shows short branches (speciate very quickly). There are three known clades of dolichophallus (morphologically distinct, molecularly indistinct). There strong differences in morphology and behavior between species but very similar molecularly. Evidence from the molecular work points to rapid evolution, possibly driven by sexual selection. Their ploidy is unknown but most likely the same across species.

• Simulatenous hermaphrodites.
• Self-fertilizing.
• Reciprocal copulation.
• Most differences in morphology are seen in the genitalia.
• Differing patterns of mating behavior:
  • Copulation time
  • Type of intromission
  • Number of copulations per encounter
  • Partner changes
  • Apophallation (5% of the time in dolichophallus)